Monday, February 25, 2013

MoAR: mostly about reality and about education, this week.

when i think about this experiment, it completely defies my intuition about human vision.

i would have thought that of all the shapes that appear in nature, something symmetric like a square or a circle would be the most readily recognised and processed ..

"
Then, in 2009, a Duke University professor demonstrated that our eyes can scan an image fastest when its shape is a golden rectangle. For instance, it’s the ideal layout of a paragraph of text, the one most conducive to reading and retention. This simple shape speeds up our ability to perceive the world, and without realizing it, we employ it wherever we can."

i also learned that there is such a thing as optimal fractaΙ densιty too.

"
Certain patterns also have universal appeal. Natural fractals — irregular, self-similar geometry — occur virtually everywhere in nature: in coastlines and riverways, in snowflakes and leaf veins, even in our own lungs. In recent years, physicists have found that people invariably prefer a certain mathematical density of fractals — not too thick, not too sparse. The theory is that this particular pattern echoes the shapes of trees, specifically the acacia, on the African savanna, the place stored in our genetic memory from the cradle of the human race. To paraphrase one biologist, beauty is in the genes of the beholder — home is where the genome is.

LIFE magazine named Jackson Pollock “the greatest living painter in the United States” in 1949, when he was creating canvases now known to conform to the optimal fractal density (about 1.3 on a scale of 1 to 2 from void to solid). Could Pollock’s late paintings result from his lifelong effort to excavate an image buried in all of our brains?"

Interestingly, this means that no matter how large the web grows, the same interconnectedness will rule. Barabási analyzed the network looking at a variety of levels—examining anywhere from a tiny slice to the full 1 trillion documents—and found that regardless of scale, the same 19-click-or-less rule applied."

well, this guy said what i said better .. and in particular, more quantitatively:

"First, student attrition rates — around 90 percent for some huge online courses — appear to be a problem even in small-scale online courses when compared with traditional face-to-face classes. Second, courses delivered solely online may be fine for highly skilled, highly motivated people, but they are inappropriate for struggling students who make up a significant portion of college enrollment and who need close contact with instructors to succeed."

.. and this excerpt offers psychological reasons for the reported attrition rates:

"Every January, millions of people join gyms that they won’t go to more than a few times before other things get in the way. The problem? “Getting fit” or “losing weight” aren’t things that happen immediately. Those gym visits require a lot of effort–we lose at least an hour of our day, we wake up with new aches and pains, and we face the embarrassment of public struggle–all for what usually amounts to very small visible results. So, despite our logic telling us that being fit is a long-term win, we quit not long after we start.The same is true for learning tech (or anything else) online. Logic tells us that expanding our knowledge via that machine learning course is a long-term win, but the lack of immediate results against the weight of “all the other stuff that’s going on” oftentimes causes us to drop out before we really get started."

this excerpt gives me a small bit of hope, that our students know themselves well enough to make good decisions about their academic careers.

"
They found students believe ”that the paper textbook remains the superior technology for studying and achieving academic success.” Print’s primary advantage is that it presents “fewer distractions,” the students said: “The paper textbook helps them to avoid the distractions of being on the computer or the Internet, the temptations associated with checking e-mail, Facebook, or surfing the Web for unrelated information.”"

1. i am very glad that some surfaces are not, say, area-minimising. (-:

"This extra surface comes to use courtesy of our especially wrinkled brains. But there’s another intriguing thing about those wrinkles: they are not spread uniformly across our heads. The front of the neocortex is more wrinkly than the back. This is intriguing, because the front of the cortex handles much of the most abstract sorts of thinking. Our brains pack extra real estate there with additional folds. And if you look at mammals in general, they tend to have more wrinkles at the front than the back."

"
By placing electrodes in the stems of petunias, the researchers showed that when a bee lands, the flower’s potential changes and remains so for several minutes. Could this be a way by which flowers tell bees another bee has recently been visiting? To their surprise, the researchers discovered that bumblebees can detect and distinguish between different floral electric fields."

in case you were wondering ..

yes, the names of well-known people and theorems are obscured. as for why, too many irrelevant Google searches find their way here.
for example, search: "mαth jοbs wιkι" but without the funny greek symbols. as of a year or two ago, this blog came up in the first few hits.